Pneumatic shock-absorber



APPLICATION FILED IUNE25. I919.

Patented Oct. 5, 1920.

Z SHEETS SHEET I.

lu u" I. HOFMANN.

PNEUMATIC SHOCK ABSORBER.

APPLICATION FILED IIIIIE25. 1919.

Patent-ed Oct. 5,1929.

2 SHEETS-SHEET 2.

III

awvawto'c made 13 to prevent split serene) EOSEF HGFI-IIAM, F TBAUIQAROCEE, $VJ'TTZERLANI 7.

PNEUTIEQTIC SHUGK-ABSOEBER.

To all whom it may concern.-

Be it known that I, Josnr HOFMANN, a citizen of Poland, and resident of Banniaroche, Switzerland, have invented certain new and useful Improvements in Pneuinatic Shock-Absorbers; and I do hereby declare the following to be a ifull,'clear, and exact description of the invention, such as yvill enable others skilled in the art to which it appertains to make and use the same, ref erence being had to the accompanying drawings, and-to letters or figures of reference marked thereon, which form a part of this specification.

My invention relates to pneumatic shock absorbers of the general type shown in in Patent No. 1,179,182, dated April 11, 1916.

The object of this invention is to lighten the structure, eliminate the movement of the pneumatic cushion container and provide means for adjusting the air pressure in the pneumatic cushion Without venting it or pumping air into it,

Referring to the drawings in which like parts are similarly designated nlgure 1 1s a vertical section of my shock absorber.

Fig. 2 is a rear view 'thereof@ Fig; 3 is a side elevation on a smaller scale,

The body frame extension 1 is provided at ts end with a plate 2, to which is bolted bolts 3 the cushion container or casting having an internal spherical surface, or nearl This casting 4: has an opening cl sed a cover 5 having threaded porits for screwing it into the 111 casting 4i, and a projecting boss; 6 formed as nut for the application of spanner or wrench to screw and unscrew the cover from the body portion or casting 4:.

The outer casing '7 of fabric, has an openii 8 in it through which the rubber lining is inserted. Zihis rubber is prow th short inflating time 10 orojectinnating valve {not shown) the as nieurnatic tires.

re casin 7 is s 11 to a Wooden plunger 1 i. scared by screw provided with a ing. I The plunger its rod moves in opening 1 in the lower portion of the spherical casting the upper end of the piunger rod Ill-i is inserted in the plunger, 12 and has a bifurcated lower end seating: ona pin 16 i;

Specification of Letters Patent.

ting 4 ani orovided with Patented Oct. 5 1920.

Appiioation filed June 25, 1919. serial No. 306,652.

a lug 17 on a lever 18 that is pivoted on a 'bolt 19 in an extension of the spherical body edges of the slot to provide bumper surfaces for the rubber buffer 24 on lever 18.

The buffer, held between two heads 25, is formed in place and then vulcanized.

The end of lever 18 is pivoted to the lower end of a shackle 26, While the upper end of this shackle is pivoted to the end of the vehicle spring 27.

Projecting from the portion of the casting extension is a lug 28 in Which is secured by nuts 29 a brace rod 30 that e tends to the shock absorber on the opposite side of the vehicle.

The nut-shaped portion .6 of

which fits a nut 32 having a peripheral flange 33 for retaining a packing ring 34. The niit 32 has an internal threaded bore into which fits the threaded end 35 of a plunger 36 Whose face 3'? bearing against the outer casing 7 of the inflatable cushion is uneven or conugated, so that "when the cushion is inflated it will conform to these corrugations when it is engaged by the plunger and prevent the plunger from r0- tating' during the rotation of nut 32.

The plunger has an internal smooth bore 38 in, which slides the head 39 of a pin i0 whose reduced end. is riveted in the end of the nut 32 as shown.

it should be noted that normally the longitndlnal axis e 1) of the lever is inclined below horizontal, while the pivot it in line oc angularly displaced above this axis ith such an arrangement the e f lever 18 at the shackle will move approxiniat v in strai rht line upward J a.

unile the pivot 16 moving an who e adius is 0--1-3 will have a rise at s a decreasing rate owing the arc-note of s deflated, the l) cover 5 is hollow and. has a cylindrical bore at 31 in the opening 8 in the outer case 7 will be exposed for the removal of the rubber sack 9, should replacement of the sack be necessary. When the parts have been replaced, the sack 9 is inflated to such a degree that the lever 18 assumes the inclination shown about midway between the stops 22 and 23. The vehicle is then ready to support a normal loa If the load is increased, it has heretofore been necessary to pump more air into the cushion. If the suspension was subsequently too stifi', it was necessary to vent some air from the cushions, and it required careful attention so as not to vent too much air and to keep the pressure in all the suspensions substantially equal.

To accomplish these ends without the use of a pump, and without venting the cushions, I have devised a. simple mechanical structure. v

After the cushions have been filled to normal and it is desired to stiffen the suspension for a load exceeding the initial load, it

is simply necessary to turn the nut 32 with a spanner or wrench, thus screwing the plunger inward to indent the cushion and. increase the air pressure. The plunger is prevented from turning by the corrugations or projections on its face engaging the cover 7. This cushion and additionally compresses the air in the cushion. The head 39 on pin 40 acts as a stop for the inward movement of the plunger and prevents the disengagement of the screw threads of the plunger and nut.

. Rotating the nut 32 in the opposite direction will permit the cushion to return to its initial volume and pressure- I claim- 1. A shock absorber having a substantially spherical body portion communicating w'th a downward extension having a slot, a lever pivoted within said extension and projecting through said slot, said lever having a pivot, a buffer carried by said lever and opera ing in said slot, buffer stops at each end of said slot, a pneumatic cushion in said body portion, a plunger for said cushion, said plunger arranged on an angularly displaced pivot, and a shackle onthe end of the lever for connecting it to a vehicle spring.

2. A shock absorber having a substantially spherical body portion communicating with a slotted downward extension substantially cylindrical at its front portion, a

* lever pivoted in the rear portion: of said its extension and extending through the slot in the cylindrical portion, the front wall of said cylindrical portion being curved with its center of curvature about at the pivot point of said lever, a pneumatic cushion in said body portion and a plunger for said cushion pivoted on said lever.

' ing a casing decreases the initial volume of the 3. In a shock absorber, a. substantially spherical body portion, a removable cover therefor, and a pneumatic cushion in said portion removable through the opening closed by said cover, said cushion comprishaving a permanent opening, and an inflatable member inse-rtible within the casing through said permanent opening.

4. In a pneumatic shock absorber, a substantially spherical body portion open at its bottom, a pneumatic cushion Within said body portion, means at one side of said body portion to connect it to the vehicle and a removable cover between the securing means. and opening in the bottom, whereby the pneumatic cushions within said body portion may be replaced without disconnecting the body portion from the vehicle. 7

5. In a shock absorber having an inflatable pneumatic cushion, means to adjust the initial volume of the cushion by mechanical pressure and thereby adjust the pressure within the cushion.

62 In a shock absorber having an inflatw ble pneumatic cushion, adjustable means to indent the cushion to decrease its initial volume and thereby adjust the pressure within the cushion.

7. Ina shock absorber having an inflatable pneumatic cushion, a container for said cushion, a removable cover for said container and means inv said cover to vary the initial volume of the cushion.

; 8. In a shock absorber having an inflatable pneumatic cushion tbinsisting of a 'flexible outer casing and an i ner inflatable rubber lining; a plunger having a roughened surface for. engaging, the outer casing and means to adjust the plunger inward and outward to vary the initial volume of the cushion l 9. Inashock absorber having an inflatable pneumatic cushion; a lunger engaging said cushion for varying he initial volume of the cushion, sald" plunger having a; threaded shank, a nut on said shankto adjust the plunger to and from the cushion, and a stop to prevent the disengagement of plunger and nut.

10. In a shock absorber, a substantially spherical casting havinga pneumatic cushion therein, a cover for said casting, a rotatable nut mounted in said cover, a plunger having a threaded shank engaging the nut, said plunger having a central bore and al pin having one end secured in said nut and removable when deflated ing in the outer casi 12. In a shock absorber Ion device rigidly evice havin through said openng and cover opening.

, a pneumatic cushsupported bya, vehicle 5 body frame, a pivoted lever inclined ben its neutral position, a

a pivotal sup port on said lever above said onzontal end pivotal means 10 vehicle spring.

13. In a shock absorber ion device supported by frame,

a lever to produce for connecting the lever to a a pneumatic cushng' leverage, and therea ter of said cushion device pro ively increasdecreusing leverage, a plunger for said device having pivotal support on said lever, offset from the axis thereof and arran ed prprogressive decreasing leverage un er All normal conditio'nsof compression and prmitting upon abnopnal emplitude of movement a'n' initillljincreilse of leveragew In testimony that-I claim the foregoing as progressively 1 JOSEF HOFMANN. 

